how can I tell how old my chickens are

I bought seven chickens from Craigslist so I could have fresh eggs. One (the black one) is laying an egg every day. One (the red one) turned out to be a rooster. The other five haven't laid any eggs. I have been feeding them mash, scratch, whole corn, and produce scraps. They live in a coop and have a fairly large run with plenty of water. They seem happy... But no eggs!! Wonder if they are too young or too old? How can I tell? I have had them for 7 weeks. [/IMG][/IMG]

I looked for mites, not sure, I will treat with olive oil spray just to be sure. Thanks!! I'm a newbie.. What do you mean "somewhat older"... Like past the egg laying stage? Neither of them have laid eggs yet since they have been with me, do you think I bought OLD chickens??

It almost looks as if they may just be finishing a molt - hard to tell from pictures. They appear to be in very good condition, and the reddening combs indicate they are 'thinking' about resuming egg laying.

At this point I think it's safe to say your birds probably won't lay again until spring, sorry. it's hard to tell the age of a hen once she's mature until she's quite a bit older, when they're in that 2-3 year stage they don't look much different.